Field of the Invention
The present invention relates to a recycling process and system for recycling machining waste into both recyclable scrap metal and recyclable machining coolant so as to facilitate complete recycling of substantially all the machining waste generated by conventional computer numerical control (CNC) machining equipment.
Description of Related Prior Art
A variety of recycling systems are currently known for recycling machining coolant which is typically used for both cooling and/or lubricating various machining tools that are utilized by conventional CNC machining equipment in a manufacturing plant or a machine shop, for example. Typically, each piece of CNC machining equipment, of a manufacturing plant or a machine shop, has a dedicated coolant recirculating system in which machining coolant is continuously supplied from a storage tank, during the machining operation, and used to cool the machining tool of the CNC machining equipment. The supplied machining coolant is then filtered and returned back to the storage tank for reuse. Periodically, the machining coolant may be checked to ensure that the machining coolant has a desired concentration and is still functioning properly in order to adequately cool and/or lubricate the various machining tools during the machining process.
During normal use, over time the machining coolant eventually becomes contaminated with various substances, e.g., due to contact of the machining coolant with the structure of the CNC machine, contact with the machining tool(s), contact with the workpiece which the machining coolant is cooling and/or lubricating, etc. These substances include, for example, particulate matter of various sizes, such as minute metal particles or shavings, larger metallic particles, shavings, debris, tramp oils, emulsifiers and/or other contaminants. To the extent possible, it is desirable to remove such contaminants from the machining coolant before the machining coolant can be turned back to the storage tank and subsequently be reused by the CNC machining equipment for cooling and/or lubricating a machining tool. Accordingly, such machining coolant is at least filtered, in a conventional manner, prior to being deposited in the storage tank for reuse by the CNC machining equipment.
The CNC machining equipment typically generates machining waste as a result of the conventional machining process of the CNC machining equipment. Such machining waste generated, as noted above, generally comprises minute metal particles or shavings, larger particles, shavings, debris, tramp oils, other contaminants and/or a small percentage of the emulsifiers/machining coolant. The generated machining waste is periodically disposed, e.g., on a daily basis for example. It is to be appreciated that such machining waste has some salvage value due to the inherent value of the metal particles contained within the machining waste. That is, such machining waste can be typically sold to a scrap metal dealer, for example. However, such scrap metal dealers generally prefer to only purchase machining waste, e.g., the scrap metal contained within the machining waste, in the event that the machining waste has a moisture content of 4% or less. It is to be appreciated that machining waste from a conventional CNC machining process, however, generally has a much higher moisture content, e.g., typically a moisture content of between 8%-20% or so, for example, and thus is somewhat more difficult to sell higher moisture content machining waste to a scrap metal dealer.
One known process for reducing the moisture content of the machining waste is to place such machining waste on top of a fine mesh screen or filter and allow gravity to assist with separating the salvageable machining coolant from the solid waste over time, e.g., typically a 24 hours time period is sufficient. While this procedure is somewhat effective in separating the machining coolant from the solid waste, gravity is only effective in reducing the moisture content, in the scrap material trapped by the fine mesh screen or filter, to comprise about 8% of the waste material. It is to be appreciated that a moisture content of about 8% is still generally too high for many scrap metal dealers and thus such high moisture content waste material is somewhat more difficult to recycle and/or tends to be less valuable.
In addition to the above, it is to be appreciated that many machining coolants comprise trade secret/proprietary formulations so that all of the actual components/constituents, forming the machining coolant, are not known. This consequentially hinders effective and efficient recycling of the machining coolant for subsequent reuse by an end user.